While 55 - 60% of newly diagnosed bladder cancers are superficial, a significant number recur as higher grade and/or stage tumors. WBPDT has been used to treat some of these recurrent superficial tumors, although its use has been associated with dose-dependent side effects. Preclinical investigation of three sequential WBPDT treatments using lower PDT dose in normal canine bladder resulted in a lack of permanent bladder contracture. Lower dose single PDT treatment has shown less durable tumor response; however, sequential WBPDT treatments with lower dose may result in durable tumor response. Five patients (4 male, 1 female), average age 65.6 (62-72 years), with recurrent or resistant superficial TCC of the bladder received two WBPDT treatments. First treatment occurred at baseline and the second treatment at 6 months. Photofrin (1.5 mg/kg) was given intravenously 48 hours prior to each cystoscopic treatment with laser light (630 nm, Coherent Lambda-Plus laser). Total light treatment doses were 1500 - 2500 Joules at baseline and 1000- 1500 Joules at 6 months. Moderate irritative bladder symptoms occurred in all patients the first week post PDT. No cases of bladder contracture have occurred. 4 of 5 patients showed no evidence of disease during the follow-up period (12 - 18 months post second treatment). One patient had a recurrence at 18 months post second treatment. Mean disease-free interval is 16.2 months. The safety of two sequential WBPDT treatments is suggested by this preliminary data. Assessment of efficacy will be possible wit a large number of patients and a longer follow-up period.